The present invention is related to a system and method of developing a can bottom profile on the basis of predetermined performance conditions and to a can with a domed bottom structure designed using said method. More specifically, the present invention relates to a method of developing a can bottom profile using finite element analysis techniques.
The profile of the bottom of a beverage can is generally defined by a series of intersecting arcs and lines. Dimensional parameters can be derived based on the size of the intersecting arcs and lines and their positions relative to one another. The dimensional parameters include such things as the radii of arcs, the degree of slant of lines and the height and length of certain intersection points relative to a fixed reference. The number of dimensional parameters used to define a profile made of such arcs and lines is typically between 10 to 20. A known generic can profile showing common parameters is shown in FIG. 2A.
Traditionally, the effectiveness of a can bottom profile was determined by trial and error. This requires the manufacturing of a prototype of a can to be used in physical testing of the performance properties of the can. The performance properties evaluated are often those of dome reversal pressure and response to axial loading. Dome reversal pressure is the amount of internal pressure required for the dome at the bottom of the can to be reversed in direction from concave to convex and depends largely on the geometrical features inside the bottom rim or stand.
Axial loading is the amount of force the can is able to withstand in the longitudinal direction and depends largely on the geometrical features outside the bottom rim or stand. If the performance properties of the current prototype do not meet the required standards then adjustments must be made to the design based on educated guessing. A new prototype for the revised design is then made and tested. This procedure is repeated until a sufficient design is made that meets the imposed standards.
The traditional trial and error method is not only a cumbersome and slow process but it is also expensive. Each time a new can bottom design is made a physical model has to be manufactured, creating a multitude of failed prototypes as the iterative procedure continued. Manufacturing prototypes takes time as with each small variation the dies used to create the prototype have to be changed or manufactured again to account for the change in design.
Recently, finite element analysis techniques have been used to examine the performance properties of structural designs. However, for a profile consisting of 13 parameters 1.5 million computer analyses would be required to examine variants of only three possible parameters. To exhaustively examine even half of the 13 parameters is not easily accomplished, even with the powerful computing power currently available.
As such, it is an object of the present invention to provide a method of developing an improved can bottom profile using a minimum number of calculations.
Another object of the present invention is to provide a system for developing an improved can bottom profile using a minimum number of calculations.
Another object of the present invention is to provide a can with a domed bottom structure to achieve resistance to failure under internal pressure and to axial load failure.
In accordance with one aspect of the present invention there is provided a method executed by a computer system as part of a computer-implemented program for developing a can design profile from a can design model represented in parametric form using a set of performance conditions and a set of design constraints, said method comprising the steps of: (a) selecting optimization conditions including parameters from the parametric form of the can design model and values for these parameters; (b) performing finite element analysis on the parametric form of the can design model; and (c) modifying the values of the selected parameters based on the results of step (b).
In accordance with another aspect of the present invention there is provided a method executed by a computer system as part of a computer-implemented program for developing a can design profile from a can design model represented in parametric form using a set of performance conditions and a set of design constraints, said method comprising the steps of: (a) selecting a plurality of optimization condition sets including parameters from the parametric form of the can design model and values for these parameters; (b) performing finite element analysis on the parametric form of the can design model using each of the optimization sets; and (c) modifying the values of the selected parameters in each optimization set based on the results of step (b).
In accordance with an additional aspect of the present invention there is provided a method of fabricating a can design profile for an article of manufacture from a can design model represented in parametric form using a set of performance indicators and a set of design constraints, said method comprising the steps of: (a) selecting optimization conditions including parameters from the parametric form of the can design model and values for these parameters; (b) performing finite element analysis on the parametric form of the can design model; (c) modifying the values of the selected parameters based on the results of step (b) and (d) converting the can design model in parametric form into the can design profile.
In accordance with a further aspect of the present invention there is provided a computer system for developing a can design profile from a can design model represented in parametric form using a set of performance conditions and a set of design constraints, said system comprising: (a) selection means for selecting optimization conditions including parameters from the parametric form of the can design model and values for these parameters; (b) finite element analysis means for performing finite element analysis on the parametric form of the can design model; (c) processing means for modifying the values of the selected parameters based on the results of step (b); and (d) conversion means for converting the can design model in parametric form into the can design profile.
In accordance with a further aspect of the present invention there is provided a metal can designed by using the aforementioned can design profile methods, said metal can comprising: a cylindrical side wall; a bottom stand having a curved base on which the can rests and connected to one end to the curved base an outside outwardly inclined bottom wall and connected to the other end of the curved base is an inside inwardly inclined bottom wall; an outside connecting wall being substantially flat and having a curved connector on each end thereof for connecting the outside connecting wall to the cylindrical side wall on one end and on the other end connecting the outside connecting wall to the outside outwardly inclined bottom wall; a concave dome-shaped bottom wall; and an inside connecting wall being substantially flat and having a curved connector on each end thereof for connecting the inside connecting wall to the concave dome-shaped bottom wall and on the other end connecting the outside connecting wall to the inside inwardly inclined bottom wall.